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Quantifying the heat flux regulation of metropolitan land use/land cover components by coupling remote sensing modeling with in situ measurement
Author(s) -
Kuang Wenhui,
Dou Yinyin,
Zhang Chi,
Chi Wenfeng,
Liu Ailin,
Liu Yue,
Zhang Renhua,
Liu Jiyuan
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2014jd022249
Subject(s) - environmental science , urban heat island , latent heat , beijing , sensible heat , heat flux , vegetation (pathology) , land cover , metropolitan area , flux (metallurgy) , atmospheric sciences , land use , meteorology , geography , heat transfer , china , ecology , materials science , archaeology , metallurgy , medicine , physics , pathology , biology , geology , thermodynamics
Quantifying the effects of urban land use/land cover with regard to surface radiation and heat flux regulation is important to ecological planning and heat stress mitigation. To retrieve the spatial pattern of heat fluxes in the Beijing metropolitan area, China, a remote sensing‐based energy balance model was calibrated with synchronously measured energy fluxes including net radiation, latent heat flux (LE), and sensible heat flux ( H ). Our model calibration approach avoided the uncertainties due to subjective judgments in previous empirical parameterization methods. The land surface temperature (LST), H , and Bowen ratio ( β ) of Beijing were found to increase along the outskirt‐suburban‐urban gradient, with strong spatial variation. LST and H were negatively correlated with vegetation fraction cover (VFC). For example, the modern high‐rise residential areas with relatively higher VFC had lower H and β than the traditional low‐rise residential areas. Our findings that indicate thermal dissipation through vegetation transpiration might play an important role in urban heat regulation. Notably, the thermal dissipating strength of vegetation (calculated as LE/VFC) declined exponentially with increased VFC. For the purpose of heat stress regulation, we recommend upgrading the traditional low‐rise residential areas to modern high‐rise residential areas and focusing urban greenery projects in areas whose VFC < 0.1, where the heat regulating service by urban vegetation could be twice as effective as in other places.